Digital oscilloscopes can be grouped into sampling oscilloscopes (also called equivalent-time oscilloscopes) and real-time oscilloscopes. Digital oscilloscopes are indispensable for testing and debugging of electronic and system designs, due to their versatility and flexibility.
The requirements for state-of-the art oscilloscopes are a higher sample rate for a better resolution of signal details and a deeper memory for capturing longer signal sequences. It gets more and more important, being able to acquire rare, random or intermittent events, which typically appear only for a short duration and infrequently.
Sampling oscilloscopes are very useful when analyzing high frequency signals such as repetitive signals whose frequencies are higher than the oscilloscopes sampling rate. Said oscilloscopes achieve their performance by collecting samples from several successive waveforms, and by then assembling them together to reconstruct the overall waveform. For each trigger event, only one sample is taken.
A real-time oscilloscope captures an entire waveform on each trigger event, thus, the real-time oscilloscope is able to capture a large number of data points in one continuous record. The real-time oscilloscope allows the user to display single or rare, random or intermittent events, which is advantageous for many measurement tasks.
One important application of digital oscilloscopes is the determination the characteristics of electrical lines, circuit board traces, connectors and so on, based on time-domain reflectometry (TDR) and time-domain transmission (TDT). Said modules are connected to a device under test (DUT) and are able to generate a fast step signal, called a fast step incident and transmit said fast step incident signal to the device under test (DUT). These modules are further capable of recording the voltage at the device under test input (DUT) and output(s) over time. At the input port, said voltage over time record represents the incident step as well as any reflections coming from the DUT. These reflections are a time-domain representation of the input reflection coefficient of the DUT. Additionally it is possible to record the voltage over time at an output port of the device under test (DUT), which is a time-domain representation of the transfer function of the device under test (DUT).
However, no real-time oscilloscopes providing such TDR and TDT modules are known, thus no real-time oscilloscopes providing a time-domain reflectometry functionality and a time-domain transmission functionality are present.
US 2016/0018450 A1 relates to a method and a system for determining scattering parameters of a device under test (DUT) using a real-time oscilloscope. In FIG. 2, the cited document discloses a system for measuring said scattering parameters, the system comprising a real-time oscilloscope connected to a synchronized trigger that is further connected to a signal generator. Moreover, a power divider is in communication with the real-time oscilloscope, the signal generator and the device under test (DUT).
However, the cited document only discloses a setup including a real-time oscilloscope with external signal generator, external power splitter, external synchronized trigger and cables to connect the single units with each other. Such a setup is expensive, difficult to calibrate, especially due to moving connection cables and cables having different lengths. It is disadvantageous that such a setup uses already two of in most cases 4 channels of the real-time oscilloscope, which reduces the possibility to perform other measurements with the real-time oscilloscope.
Accordingly, there is a need to provide a real-time oscilloscope with a built-in time domain reflectometry (TDR) and/or time-domain transmission (TDT) function to overcome said deficiencies.